title: Golgi nucleotide sugar transporter modulates cell wall biosynthesis and plant growth in rice.
abstract: Golgi-localized nucleotide sugar transporters (NSTs) are considered essential for the biosynthesis of wall polysaccharides and glycoproteins based on their characteristic transport of a large number of nucleotide sugars to the Golgi lumen. The lack of NST mutants in plants has prevented evaluation of this hypothesis in plants. A previously undescribed Golgi NST mutant, brittle culm14 (bc14), displays reduced mechanical strength caused by decreased cellulose content and altered wall structure, and exhibits abnormalities in plant development. Map-based cloning revealed that all of the observed mutant phenotypes result from a missense mutation in a putative NST gene, Oryza sativa Nucleotide Sugar Transporter1 (OsNST1). OsNST1 was identified as a Golgi-localized transporter by analysis of a fluorescence-tagged OsNST1 expressed in rice protoplast cells and demonstration of UDP-glucose transport activity via uptake assays in yeast. Compositional sugar analyses in total and fractionated wall residues of wild-type and bc14 culms showed a deficiency in the synthesis of glucoconjugated polysaccharides in bc14, indicating that OsNST1 supplies the glucosyl substrate for the formation of matrix polysaccharides, and thereby modulates cellulose biosynthesis. OsNST1 is ubiquitously expressed, with high expression in mechanical tissues. The inferior mechanical strength and abnormal development of bc14 plants suggest that OsNST1 has pleiotropic effects on cell wall biosynthesis and plant growth. Identification of OsNST1 has improved our understanding of how cell wall polysaccharide synthesis is regulated by Golgi NSTs in plants.
authors.affiliation: State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Baocai
authors.initials: B
authors.lastname: Zhang
authors.forename: Xiangling
authors.initials: X
authors.lastname: Liu
authors.forename: Qian
authors.initials: Q
authors.lastname: Qian
authors.forename: Lifeng
authors.initials: L
authors.lastname: Liu
authors.forename: Guojun
authors.initials: G
authors.lastname: Dong
authors.forename: Guangyan
authors.initials: G
authors.lastname: Xiong
authors.forename: Dali
authors.initials: D
authors.lastname: Zeng
authors.forename: Yihua
authors.initials: Y
authors.lastname: Zhou
mesh_terms: D001692:Biological Transport / Q000502:physiology; D002473:Cell Wall / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D006056:Golgi Apparatus / Q000235:genetics / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D020125:Mutation, Missense; D012275:Oryza / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D011134:Polysaccharides / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D026901:Membrane Transport Proteins; D010940:Plant Proteins; D011134:Polysaccharides